Every ESP sells dedicated IPs as a premium add-on. The pitch is simple: your own IP means your reputation is entirely yours. No noisy neighbors sending spam on the same IP and dragging your deliverability down.
That's true. But it's not the whole story.
How email reputation works
ISPs (Gmail, Outlook, Yahoo) assign reputation scores to the IP addresses that send email. A high-reputation IP gets inbox placement. A low-reputation IP gets spam-foldered or blocked.
On a shared IP, your reputation is pooled with other senders. If someone else on the same IP sends spam, your deliverability suffers. But the upside is that the IP already has an established sending history. ISPs know it. They trust it (or at least, they have data on it).
On a dedicated IP, you start from zero. ISPs have no history for your IP. No reputation means no trust.
The warmup problem
A brand-new IP has no reputation. If you start sending 50,000 emails on day one, ISPs will treat it as suspicious and block most of them.
The standard warmup schedule looks like this:
| Week | Daily volume |
|---|---|
| 1 | 50–100 |
| 2 | 200–500 |
| 3 | 500–1,000 |
| 4 | 1,000–5,000 |
| 5 | 5,000–10,000 |
| 6 | 10,000+ |
That's 41+ days before you can send at full volume. During warmup, you need to send only to your most engaged recipients — people who will open and click. Any bounces or spam complaints during warmup have an outsized negative impact.
Most senders underestimate how painful this is. If you have a product launch scheduled and you just got a dedicated IP, you're going to have a bad time.
When dedicated IPs make things worse
Low volume senders — If you send fewer than 50,000 emails per month, a dedicated IP will likely hurt you. ISPs need consistent sending volume to maintain reputation. Sporadic sends from a dedicated IP look suspicious. A shared IP with steady traffic from multiple senders actually performs better.
Inconsistent senders — If you send a newsletter once a month but nothing in between, your IP reputation decays between sends. Each send feels like a mini-warmup.
Senders who can't segment during warmup — If you can't identify your most engaged contacts to use during the warmup period, you'll poison the IP's reputation from day one.
When dedicated IPs actually help
High volume, consistent senders (100k+/month) — If you're sending at scale every day, you generate enough data for ISPs to build and maintain a reputation. At this volume, isolating your traffic makes sense.
Separation of mail streams — If you send both transactional (password resets, receipts) and marketing email, putting them on separate IPs prevents a bad marketing campaign from affecting your transactional deliverability.
Compliance requirements — Some industries require dedicated infrastructure for audit trails and compliance. A dedicated IP gives you a clean paper trail.
PushMail's approach
We don't push dedicated IPs on everyone. Our default architecture already provides reputation isolation:
Subuser isolation — Every PushMail organization gets its own SendGrid subuser. Your sending reputation is tracked separately from other PushMail customers. This gives you most of the benefits of a dedicated IP without the warmup pain.
Shared IP pool with isolation — Our managed sending uses SendGrid's shared IP pool, but because each org has its own subuser, reputation impact is isolated. If another PushMail customer has deliverability issues, it doesn't affect you.
Dedicated IPs as an add-on — For senders doing 100k+ emails/month who want full IP isolation, we offer dedicated IPs at $40/month. We handle the warmup automation — gradually ramping volume over 6 weeks. You don't need to manage warmup schedules manually.
BYOK for full control — If you already have a SendGrid account with warmed IPs, use BYOK mode. Bring your own key, keep your existing IP reputation, and use PushMail for sequences, campaigns, and contact management.
The bottom line
If you send fewer than 100,000 emails per month, you almost certainly don't need a dedicated IP. Our subuser isolation gives you clean reputation tracking without the warmup overhead.
If you do need one, we'll set it up and handle the warmup. But we won't upsell you on infrastructure you don't need.